用xutils3.0进行下载

写的例子比较简单，是用xutils3.0来进行下载项目更新

1.先通过网络请求，判断版本是否要更新

2.若要更新，则弹出一个弹窗，我用的是系统自带的Dialog，将下载的版本号及下载的内容提示展示出来

3.当用户点击下载时，开始下载，下载时展示一个水平的进度条

4.下载完成后，进度条消失，调用系统安装apk

如下是代码  用到的xutils的jar包是3.3.32版本的

 package com.item.weixin;

 import java.io.File;

 import org.json.JSONException;
 import org.json.JSONObject;
 import org.xutils.x;
 import org.xutils.common.Callback;
 import org.xutils.http.RequestParams;

 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Environment;
 import android.view.View;
 import android.view.Window;
 import android.widget.Button;

 /**
  * 设置xutils下载
  *
  * @author Administrator
  *
  */
 public class LoginActivity extends Activity {
     private Button ll_update;
     private ProgressDialog pDialog;
     private String nowVersion;
     private ProgressDialog progressDialog;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.activity_login);
         ll_update = (Button) findViewById(R.id.btn_login);
         ll_update.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View arg0) {
                 // TODO Auto-generated method stub
                 checkUpdate();
             }
         });
         try {
             PackageInfo packageInfo = getPackageManager().getPackageInfo(
                     getPackageName(), 0);
             nowVersion = packageInfo.versionName;
         } catch (NameNotFoundException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     /**
      * 下载更新,
      */
     protected void checkUpdate() {
         // TODO Auto-generated method stub
         proDialogShow(LoginActivity.this, "正在查询...");
         RequestParams params = new RequestParams("url");
         x.http().get(params, new Callback.CommonCallback<String>() {

             @Override
             public void onCancelled(CancelledException arg0) {
                 // TODO Auto-generated method stub

             }

             @Override
             public void onError(Throwable arg0, boolean arg1) {
                 // TODO Auto-generated method stub
                 PDialogHide();
                 System.out.println("提示网络错误");
             }

             @Override
             public void onFinished() {
                 // TODO Auto-generated method stub

             }

             @Override
             public void onSuccess(String arg0) {
                 // TODO Auto-generated method stub
                 PDialogHide();
                 try {
                     JSONObject object = new JSONObject(arg0);
                     boolean success = object.getBoolean("succee");
                     if (success) {
                         String desc = object.getString("desc");
                         String downloadurl = object.getString("downloadurl");
                         String versionname = object.getString("versionname");
                         if (nowVersion.equals(versionname)) {
                             System.out.println("当前版本为最新，不用跟新");
                         } else {
                             // 不同，弹出更新提示对话框
                             setUpDialog(versionname, downloadurl, desc);
                         }
                     }
                 } catch (JSONException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         });
     }

     /**
      *
      * @param versionname
      *            地址中版本的名字
      * @param downloadurl
      *            下载包的地址
      * @param desc
      *            版本的描述
      */
     protected void setUpDialog(String versionname, final String downloadurl,
             String desc) {
         // TODO Auto-generated method stub
         AlertDialog dialog = new AlertDialog.Builder(this).setCancelable(false)
                 .setTitle("下载" + versionname + "版本").setMessage(desc)
                 .setNegativeButton("取消", null)
                 .setPositiveButton("下载", new DialogInterface.OnClickListener() {

                     @Override
                     public void onClick(DialogInterface arg0, int arg1) {
                         // TODO Auto-generated method stub
                         setDownLoad(downloadurl);
                     }
                 }).create();
         dialog.show();
     }

     /**
      * 下载包
      *
      * @param downloadurl
      *            下载的url
      *
      */
     @SuppressLint("SdCardPath")
     protected void setDownLoad(String downloadurl) {
         // TODO Auto-generated method stub
         RequestParams params = new RequestParams(downloadurl);
         params.setAutoRename(true);//断点下载
         params.setSaveFilePath("/mnt/sdcard/demo.apk");
         x.http().get(params, new Callback.ProgressCallback<File>() {

             @Override
             public void onCancelled(CancelledException arg0) {
                 // TODO Auto-generated method stub

             }

             @Override
             public void onError(Throwable arg0, boolean arg1) {
                 // TODO Auto-generated method stub
                 if(progressDialog!=null && progressDialog.isShowing()){
                     progressDialog.dismiss();
                 }
                 System.out.println("提示更新失败");
             }

             @Override
             public void onFinished() {
                 // TODO Auto-generated method stub

             }

             @Override
             public void onSuccess(File arg0) {
                 // TODO Auto-generated method stub
                 if(progressDialog!=null && progressDialog.isShowing()){
                     progressDialog.dismiss();
                 }
                 Intent intent = new Intent(Intent.ACTION_VIEW);
                 intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                 intent.setDataAndType(Uri.fromFile(new File(Environment
                         .getExternalStorageDirectory(), "demo.apk")),
                         "application/vnd.android.package-archive");
                 startActivity(intent);
             }

             @Override
             public void onLoading(long arg0, long arg1, boolean arg2) {
                 // TODO Auto-generated method stub
                 progressDialog.setMax((int)arg0);
                 progressDialog.setProgress((int)arg1);
             }

             @Override
             public void onStarted() {
                 // TODO Auto-generated method stub
                 System.out.println("开始下载");
                 progressDialog = new ProgressDialog(LoginActivity.this);
                 progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);//设置为水平进行条
                 progressDialog.setMessage("正在下载中...");
                 progressDialog.setProgress(0);
                 progressDialog.show();
             }

             @Override
             public void onWaiting() {
                 // TODO Auto-generated method stub

             }
         });
     }

     private void proDialogShow(Context context, String msg) {
         pDialog = new ProgressDialog(context);
         pDialog.setMessage(msg);
         // pDialog.setCancelable(false);
         pDialog.show();
     }

     private void PDialogHide() {
         try {
             if (pDialog != null && pDialog.isShowing()) {
                 pDialog.dismiss();
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }